This invention relates to polyurethane polymers. This invention particularly relates to polyurethane polymers obtained from aqueous polyurethane dispersions.
Polyurethane dispersions are known, and can be used to obtain polyurethane polymers that can themselves be useful in various applications. Polyurethane/urea dispersions can be used to obtain, for example: carpet backings; coatings for wood finishing; glass fiber sizing; textiles; adhesives; automotive topcoats and primers; films for packaging; gloves, and other applications. Polyurethane dispersions can be prepared by various processes, including, for example, those described in: U.S. Pat. No. 4,857,565; U.S. Pat. No. 4,742,095; U.S. Pat. No. 4,879,322; U.S. Pat. No. 3,437,624; U.S. Pat. No. 5,037,864; U.S. Pat. No. 5,221,710; U.S. Pat. No. 4,237,264; and, U.S. Pat. No. 4,092,286.
Polyurethane dispersions can be obtained according to a process that is described in U.S. application Ser. No. 09/039978. Dispersions prepared according to the process described therein can be useful for obtaining polyurethane carpet backings and polyurethane textile backings. Problems can result, however, in the event that a spill occurs wherein a liquid can flow onto, or be absorbed by, the backing on the underside of a carpet. Spilled liquids such as water, urine, beverage drinks, food, blood, and feces can penetrate a carpet backing to the underside of the carpet, which can be inaccessible to various cleaning methods. Polymeric materials having moisture resistance can be useful in protective wear such as gloves, for example, or packaging.
Various conventional methods can provide a moisture barrier to polymers obtained from aqueous polymeric dispersions. For example, increased coating weights of a dispersion can be used, thereby increasing the thickness of the polymer. Alternatively, wax added to an aqueous polymeric dispersion can provide a moisture barrier to carpet. Another known method for providing a moisture barrier is to decrease the amount of filler used in a carpet backing formulation. A non-permeable fabric or film can also be applied to a carpet backing, as described in U.S. Pat. No. 5,763,040. Still another method involves applying a fluorochemical on the underside of a secondary backing, and is described in U.S. Pat. No. 5,348,785. Use of fluorochemicals to impart water impermeability is also described in U.S. Pat. Nos. 4,619,853 and 4,643,930. A water-impervious film is described in U.S. Pat. No. 4,336,089. Application of various hydrophobic compositions to a secondary backing is described in U.S. Pat. No. 5,558,916.
It would be desirable in the art of preparing polyurethane polymers, to prepare a polyurethane dispersion that includes a component that imparts a moisture barrier to a polyurethane polymer, without adding complexity to a manufacturing process, or significantly changing the other properties of the polyurethane polymer. It would also be desirable in the art to prepare such a polymer by a process that would not significantly increase the cost of manufacture of the polymer, or articles produced therefrom.